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path: root/Documentation/video4linux/v4l2-framework.txt
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2010-10-21[media] radio-mr800: fix locking orderHans Verkuil
Don't hold the lock before unregistering the device, since when the device is unregistered the datastruct containing the lock may be freed (if the refcount went to 0). Also fixed the framework documentation that erroneously suggested the wrong locking order as well. Reported-by: David Ellingsworth <david@identd.dyndns.org> Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Acked-by: David Ellingsworth <david@identd.dyndns.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-10-21V4L/DVB: v4l2: add core serialization lockHans Verkuil
Drivers can optionally set a pointer to a mutex in struct video_device. The core will use that to lock before calling open, read, write, unlocked_ioctl, poll, mmap or release. Updated the documentation as well and ensure that v4l2-event knows about the lock: it will unlock it before doing a blocking wait on an event and relock it afterwards. Ensure that the 'video_is_registered' check is done when the lock is held: a typical disconnect will take the lock as well before unregistering the device nodes, so to prevent race conditions the video_is_registered check should also be done with the lock held. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-10-21V4L/DVB: v4l2-dev: after a disconnect any ioctl call will be blockedHans Verkuil
Until now all fops except release and (unlocked_)ioctl returned an error after the device node was unregistered. Extend this as well to the ioctl fops. There is nothing useful that an application can do here and it complicates the driver code unnecessarily. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-10-21V4L/DVB: Documentation: update now that the vtx/videotext API has been removedHans Verkuil
Remove all references to /dev/vtx in the documentation, except for some historical comments in dev-teletext.xml. Documentation/devices.txt is not updated, this will go through Alan Cox who maintains this file. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-10-21V4L/DVB: v4l: Add a v4l2_subdev host private data fieldLaurent Pinchart
The existing priv field stores subdev private data owned by the subdev driver. Host (bridge) drivers might need to store per-subdev host-specific data, such as a pointer to platform data. Add a v4l2_subdev host_priv field to store host-specific data, and rename the existing priv field to dev_priv. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-05-19V4L/DVB: V4L: Events: Add documentationSakari Ailus
Add documentation on how to use V4L2 events, both for V4L2 drivers and for V4L2 applications. Signed-off-by: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-05-19V4L/DVB: V4L: File handles: Add documentationSakari Ailus
Add documentation on using V4L2 file handles (v4l2_fh) in V4L2 drivers. Signed-off-by: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-05-19V4L/DVB: v4l2-framework.txt: fix incorrect statementHans Verkuil
After unregister_device all fileops are blocked, except for ioctls. So it is not just the open that is blocked, others are as well. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-02-26V4L/DVB: V4L2 docs: replace spaces by tabsMauro Carvalho Chehab
CC: Jonathan Corbet <corbet@lwn.net> CC: Reviewed-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-02-26V4L/DVB: V4L2: Add a document describing the videobuf layerJonathan Corbet
Videobuf is a moderately complex API which most V4L2 drivers should use, but its documentation is...sparse. This document attempts to improve the situation. Signed-off-by: Jonathan Corbet <corbet@lwn.net> Reviewed-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-12-16V4L/DVB (13549): v4l: Add video_device_node_name functionLaurent Pinchart
Many drivers access the device number (video_device::v4l2_devnode::num) in order to print the video device node name. Add and use a helper function to retrieve the video_device node name. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-09-19V4L/DVB (12725): v4l: warn when desired devnodenr is in use & add _no_warn ↵Hans Verkuil
function Warn when the desired device node number is already in use, except when the new video_register_device_no_warn function is called since in some use-cases that warning is not relevant. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-09-19V4L/DVB (12722): v4l2-dev: replace 'kernel number' by 'device node number'.Hans Verkuil
The term 'kernel number' is very vague, so replace it with the somewhat more descriptive term 'device node number'. In one place the local variable 'nr' was used to create the device node number of the new device name. This has been replaced with the vdev->num field to more clearly mark this as being the device node number and not the minor number. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-09-19V4L/DVB (12541): v4l: remove video_register_device_indexHans Verkuil
video_register_device_index is never actually called, instead the stream index number is always calculated automatically. This patch removes this function and simplifies the internal get_index function since that can now always just return the first free index. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-09-19V4L/DVB (12540): v4l: simplify v4l2_i2c_new_subdev and friendsHans Verkuil
Rewrite v4l2_i2c_new_subdev as a simplified version of v4l2_i2c_new_subdev_cfg and remove v4l2_i2c_new_probed_subdev and v4l2_i2c_new_probed_subdev_addr. This simplifies this API substantially. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-06-23V4L/DVB (12128): v4l2: update framework documentation.Hans Verkuil
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-06-16V4L/DVB (11671): v4l2: add v4l2_device_set_name()Hans Verkuil
Add a utility function that can be used to setup the v4l2_device's name field in a standard manner. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-04-06V4L/DVB (11373): v4l2-common: add explicit v4l2_device pointer as first arg ↵Hans Verkuil
to new_(probed)_subdev The functions v4l2_i2c_new_subdev and v4l2_i2c_new_probed_subdev relied on i2c_get_adapdata to return the v4l2_device. However, this is not always possible on embedded platforms. So modify the API to pass the v4l2_device pointer explicitly. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-04-06V4L/DVB (11367): v4l2-common: remove legacy codeHans Verkuil
Now that all drivers are converted to v4l2_subdev we can remove legacy code in v4l2-common. Also move the documentation of the internal API to v4l2-subdev.h where it really belongs. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-04-06V4L/DVB (11351): v4l: use usb_interface for v4l2_device_registerJanne Grunau
If usb_interface.dev is used as dev parameter for v4l2_device_register v4l2_dev.name contains the v4l driver/module name and usb device and interface instead of a simple "usb x-y". It also matches the recommendation to set the parent devices for usb drivers. Signed-off-by: Janne Grunau <j@jannau.net> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-03-30V4L/DVB (11044): v4l2-device: add v4l2_device_disconnectHans Verkuil
Call v4l2_device_disconnect when the parent of a hotpluggable device disconnects. This ensures that you do not have a pointer to a device that is no longer present. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-03-30V4L/DVB (11021): v4l2-device: add a notify callback.Hans Verkuil
Add a notify callback to v4l2_device to let sub-devices notify their parent of special events. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-03-30V4L/DVB (10988): v4l2-dev: use parent field if the v4l2_device has no parent ↵Hans Verkuil
set. Normally the parent device of v4l2_device is used as the video device node's parent. But if it was not set, then use the parent field in the video_device struct. This is needed in the cx88 driver, which has one core v4l2_device but creates multiple pci devices (one each for raw and mpeg video). So you cannot associate the core v4l2_device with a particular PCI device, but you can do that for each video_device. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-03-30V4L/DVB (10980): doc: improve the v4l2-framework documentation.Hans Verkuil
Emphasize the need to call i2c_set_adapdata and clarify the use of the chipid in v4l2_i2c_new_(probed_)device(). Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-03-30V4L/DVB (10644): v4l2-subdev: rename dev field to v4l2_devHans Verkuil
Remain consistent in the naming: fields pointing to v4l2_device should be called v4l2_dev. There are too many device-like entities without adding to the confusion by mixing naming conventions. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-03-30V4L/DVB (10643): v4l2-device: allow a NULL parent device when registering.Hans Verkuil
Some drivers (e.g. for ISA devices) have no parent device because there is no associated bus driver. Allow the parent device to be NULL in those cases when registering v4l2_device. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-03-30V4L/DVB (10571): v4l2-framework.txt: Fixes the videobuf init functionsMauro Carvalho Chehab
Documents the driver usage functions, instead of the generic one used by the videobuf specific handlers. Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-03-30V4L/DVB (10570): v4l2-framework: documments videobuf usage on driversMauro Carvalho Chehab
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-03-30V4L/DVB (10489): doc: use consistent naming conventions for vdev and v4l2_dev.Hans Verkuil
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-03-30V4L/DVB (10252): v4l2 doc: explain why v4l2_device_unregister_subdev() has ↵Hans Verkuil
to be called. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-01-02V4L/DVB (10141): v4l2: debugging API changed to match against driver name ↵Hans Verkuil
instead of ID. Since the i2c driver ID will be removed in the near future we have to modify the v4l2 debugging API to use the driver name instead of driver ID. Note that this API is not used in applications other than v4l2-dbg.cpp as it is for debugging and testing only. Should anyone use the old VIDIOC_G_CHIP_IDENT, then this will be logged with a warning that it is deprecated and will be removed in 2.6.30. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-01-02V4L/DVB (10136): v4l2 doc: update v4l2-framework.txtHans Verkuil
Mention the new v4l2_file_operations struct. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-01-02V4L/DVB (10134): v4l2 doc: set v4l2_dev instead of parent.Hans Verkuil
Update the documentation now that the v4l2_dev field is in. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-01-02V4L/DVB (10133): v4l2-framework: use correct comment style.Hans Verkuil
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-12-30V4L/DVB (9943): v4l2: document video_device.Hans Verkuil
Add the missing video_device documentation to v4l2-framework.txt. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-12-30V4L/DVB (9820): v4l2: add v4l2_device and v4l2_subdev structs to the v4l2 ↵Hans Verkuil
framework. Start implementing a proper v4l2 framework as discussed during the Linux Plumbers Conference 2008. Introduces v4l2_device (for device instances) and v4l2_subdev (representing sub-device instances). Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Reviewed-by: Laurent Pinchart <laurent.pinchart@skynet.be> Reviewed-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Reviewed-by: Andy Walls <awalls@radix.net> Reviewed-by: David Brownell <david-b@pacbell.net> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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